The two-way shape memory behaviour of semicrystalline networks was investigated on systems based on poly(e-caprolactone) featuring significantly different network architecture. Crosslinked poly(e-caprolactone)s were prepared by thermal curing from methacrylic end-capped linear chains having various methacrylation degrees. By conveniently reducing the methacrylation degree, the crosslink density of cured materials was varied over a range of one order of magnitude, leading to comparable changes in the material compliance in the rubbery region, but only to moderate variations in melting and crystallization temperatures (Tm and Tc) and in the crystallinity content. When subjected to constant non-zero stress and to cooling–heating cycles from above Tm to below Tc, the materials undergo a reversible two-way elongation–contraction effect, whose extent depends on material structure and applied stress. The structural changes in the crystalline phase accompanying the cooling-induced elongation were studied through differential scanning calorimetry and X-ray diffraction analyses. The elongation process involves different contributions of entropy- and crystallization-driven processes, whose amounts were investigated as a function of the loading conditions and the molecular architecture. The role of the network density towards a controlled two-way response is evidenced, showing that a proper value of the crosslink density has to be identified to maximize the two-way elongation capabilities.
|Data di pubblicazione:||2016|
|Titolo:||The two-way shape memory behaviour of crosslinked poly(e-caprolactone) systems with largely varied network density|
|Autori:||Pandini, S.; Dioni, D.; Paderni, K.; Messori, M.; Toselli, M.; Bontempi, E.; Ricco, T.|
|Digital Object Identifier (DOI):||10.1177/1045389X15591384|
|Appare nelle tipologie:||Articolo su rivista|
File in questo prodotto:
|Journal of Intelligent Material Systems and Structures-2015-Pandini-1045389X15591384.pdf||Versione editoriale||Administrator Richiedi una copia|
I documenti presenti in Iris Unimore sono rilasciati con licenza Creative Commons Attribuzione - Non commerciale - Non opere derivate 3.0 Italia, salvo diversa indicazione.
In caso di violazione di copyright, contattare Supporto Iris